This invention relates to shaft couplings, and more particularly to a flexible coupling having provision for adjustment of the relative rotational position of the shafts being connected.
It is common to employ flexible couplings to connect shafts in drive trains so that parallel, angular, and axial misalignments can be accommodated. The flexible couplings may also provide torsional flexibility for dampening shock loads. Two common forms of flexible couplings are the gear tooth coupling and the flexible grid coupling. Both forms use a pair of hubs, one of which is mounted on each of the shafts being coupled. In the gear tooth coupling, a sleeve having internal gear teeth mates with external gear teeth formed on the hubs. In the flexible grid type, a serpentine grid has its parallel rungs received in axially directed slots formed in the hubs. An example of the latter form of flexible coupling is found in U.S. Pat. No. 3,079,773 issued Mar. 5, 1963 to Walter P. Schmitter for "Coupling."
At times it is necessary that the shafts being coupled be capable of being rotationally positioned relative to each other. On example is found where two drive trains, driven from a common source, are connected to a pair of rolls which require synchronization. Another example is found where there is a common load, such as a ball mill, which is driven from two prime movers and it is either necessary or desirable to be able to divide the load equally by fine adjustment of one or the other drive trains.
In either case, with the standard flexible coupling of either the gear or flexible grid type, it is necessary to rotationally align the shafts prior to the completion of installation of the coupling. Even then the degree of alignment which is possible is dependent on the pitch of the mating gear teeth in a gear coupling or the angular distance between consecutive slots in a flexible grid coupling. Such positioning allows only relatively course alignment.
The present invention provides a flexible coupling which permits extremely fine adjustment between the rotational positions of the shafts being coupled.